Salvianolates are the water-soluble active components of Salvia miltiorrhiza, and have been widely used clinically thanks to their significant biological activities such as antioxidation, anti-platelet aggregation and anti-atherosclerosis. Among these salvianolates, magnesium lithospermate B (or magnesium salvianolate B, MLB) is the primary chemical component.

However, there has been no report on purification/separation methods for the industrial preparation of high purity magnesium lithospermate B. For example, the Chinese patent CN1911272A reported a powder injection preparation containing high purity depside salts from Salvia miltiorrhiza and a preparation method thereof. Nevertheless, the content of magnesium lithospermate B is only of 50-95%, and the higher the content of magnesium lithospermate B was, the lower the yield was. Namely, the industrial production costs for obtaining high purity magnesium lithospermate B will be very expensive.
In addition, no medicament using substantially pure magnesium lithospermate B (high purity above 95%) as an active component has been reported in the prior art.
Therefore, developing a simple and stable process for preparing magnesium lithospermate B in high yield is needed; particularly, it is highly needed to improve the yield while preparing high purity (>95%) magnesium lithospermate B.